/*
 * Copyright 2015 The Closure Compiler Authors
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
/**
 * @fileoverview Externs for Page Visibility.
 *
 * @see http://www.w3.org/TR/page-visibility
 * @externs
 */

/**
 * Set of possible values: 'hidden', 'visible', 'prerender', 'unloaded'.
 * @typedef {string}
 * @see http://www.w3.org/TR/page-visibility/#VisibilityState
 */
var VisibilityState;
